To determine the concentration of levetiracetam in the blood to establish an individualized dose; to detect toxicity or verify that you are taking the medication as prescribed (compliance); to monitor during health changes that may affect drug clearance and/or kidney function

When To Get Tested?

Initially when establishing dosage; when indicated to detect low or excessive (potentially toxic) concentrations; when you have decreased kidney function; sometimes to verify compliance

Sample Required?

A blood sample drawn from a vein in your arm, typically just before your next dose

Test Preparation Needed?

None

You may be able to find your test results on your laboratory's website or patient portal. However, you are currently at Lab Tests Online. You may have been directed here by your lab's website in order to provide you with background information about the test(s) you had performed. You will need to return to your lab's website or portal, or contact your healthcare practitioner in order to obtain your test results.

Lab Tests Online is an award-winning patient education website offering information on laboratory tests. The content on the site, which has been reviewed by laboratory scientists and other medical professionals, provides general explanations of what results might mean for each test listed on the site, such as what a high or low value might suggest to your healthcare practitioner about your health or medical condition.

The reference ranges for your tests can be found on your laboratory report. They are typically found to the right of your results.

If you do not have your lab report, consult your healthcare provider or the laboratory that performed the test(s) to obtain the reference range.

Laboratory test results are not meaningful by themselves. Their meaning comes from comparison to reference ranges. Reference ranges are the values expected for a healthy person. They are sometimes called "normal" values. By comparing your test results with reference values, you and your healthcare provider can see if any of your test results fall outside the range of expected values. Values that are outside expected ranges can provide clues to help identify possible conditions or diseases.

While accuracy of laboratory testing has significantly evolved over the past few decades, some lab-to-lab variability can occur due to differences in testing equipment, chemical reagents, and techniques. This is a reason why so few reference ranges are provided on this site. It is important to know that you must use the range supplied by the laboratory that performed your test to evaluate whether your results are "within normal limits."

Levetiracetam is a drug that is used to treat certain seizure disorders (epilepsy) such as: juvenile myoclonic epilepsy, temporal lobe epilepsy, complex partial seizures, myoclonic seizures, refractory seizures, secondarily generalized seizures, simple partial seizures, tonic-clonic seizures. The drug is prescribed as a secondary (adjunctive) treatment in combination with other antiepileptic drugs. This test measures the amount of levetiracetam in the blood.

Epilepsy affects the brain's ability to transmit electrical impulses and to regulate nerve activity. During a seizure, a person may experience changes in consciousness, alterations in sight, smell, and taste, and may experience convulsions. The frequency of seizures varies from a single episode, to occasional seizures, to recurrent seizures. Seizures are categorized by the parts of the brain and body that are affected. Levetiracetam is prescribed to help prevent specific types of recurrent seizures.

Levetiracetam is one of several newer second-generation antiepileptic drugs. It has a wider therapeutic range than many existing first-generation seizure medications. That is, the range of concentration in the blood in which the drug is effective without being toxic is broader, making it somewhat safer. It is also associated with fewer severe side effects and does not interact with as many other drugs. Levetiracetam provides a combination of efficacy and safety that is superior to other treatment choices in many clinical circumstances.

Because levetiracetam has a wider therapeutic range, it does not need to be monitored in the same manner as first-generation antiepileptic drugs. (For further discussion of this, see the article on Therapeutic Drug Monitoring.)

At the start of therapy, doses of levetiracetam may be gradually increased until a standard amount is reached. Once a stable dose is achieved, a blood level may be measured to ensure that it is within the therapeutic range. Since levetiracetam is an adjunct (secondary) medication, the healthcare practitioner will consider the effectiveness of both drugs that are prescribed and adjust them as necessary.

How is the sample collected for testing?

A blood sample is obtained by inserting a needle into a vein in the arm.

Is any test preparation needed to ensure the quality of the sample?

This test is used to measure the amount of levetiracetam in the blood to determine whether the level of drug is within the therapeutic range. Initially, the test may be ordered to help establish the appropriate dose for an individual. Since the therapeutic range is relatively wide and not well established, the healthcare practitioner will evaluate the effectiveness of the dose in controlling seizures and the presence and severity of side effects in the individual. Depending on these clinical findings and the results of the blood test, the dose of drug may be adjusted up or down.

Routine periodic monitoring of levetiracetam is usually not required. However, there are circumstances in which it is useful and sometimes necessary to measure blood levels. Some of these include:

To establish the range that is therapeutic for an individual (dose individualization); after treatment has started and the individual has relief from symptoms (no seizures) and suffers no side effects, the concentration of the drug in the blood is determined. The range around this value is considered therapeutic for the person and may be used to evaluate that person's treatment in the future if the person's health status or other factors change.

To verify that a person's symptoms (seizures or side effects) are not due to too little or too much drug; to verify that a person is taking the medication as prescribed

To evaluate and adjust the dose as necessary in certain conditions such as:

Kidney disease—levetiracetam is cleared from the body by the kidneys, so anything that affects kidney function can affect blood levels of the drug.

A change or addition of other drugs

Aging—people typically are prescribed seizure medications for life and, as they age, the amount of drug needed to be effective may change.

A healthcare practitioner may use a levetiracetam test to help evaluate someone who is experiencing side effects or adverse reactions or experiencing a recurrence of seizures or symptoms. In some cases, testing may be ordered to verify that the person is taking the medication as prescribed (compliance).

Levetiracetam tests may occasionally be ordered after a person begins taking the drug and a stable dose is achieved. Additional levetiracetam tests may be ordered when dosages of the drug are changed and sometimes when the treated person starts or stops taking additional medications in order to judge their effect, if any, on the levetiracetam level.

Tests may be ordered periodically when a person has decreased kidney function, has an underlying condition that may affect kidney function, and/or has significant liver dysfunction.

It may be ordered when a person does not appear to be responding to therapy and has a recurrence of seizures. The blood level may not be high enough, the person may not be taking the medication as prescribed, or the drug may be ineffective for that person.

Levetiracetam tests may also be ordered when a person experiences a troublesome level of side effects and/or develops complications. Side effects that may be seen at any dose but that are related to higher concentrations include:

Most common

Aggression

Depression

Dizziness

Drowsiness

Headache

Other symptoms

Anxiety

Diarrhea

Hallucinations

Lack of coordination

Loss of appetite

Memory problems

Numbness, tingling, or burning in the hands or feet

Rash

Thoughts of suicide

Weakness

People who take levetiracetam should talk to their healthcare practitioner about the timing of the sample collection. Often, the recommended time is just before the next dose is taken (trough level).

The therapeutic range for levetiracetam is about 12.0 - 46.0 mcg/mL (mg/L). Levels above 46 mcg/mL are considered potentially toxic. Ranges vary slightly from laboratory to laboratory. Healthcare practitioners and people tested should use the therapeutic ranges and units established by the laboratory that performs the testing. Toxic levels have not been well established. Therapeutic ranges are based on the specimen immediately before the next dose (trough levels).

Within the therapeutic range, most people will respond to the drug without excessive side effects; however, response varies with each individual. Some people will experience seizures at the low end of the therapeutic range, some will experience excessive side effects at the upper end, and some will require dosages outside of the established range for effectiveness and/or freedom from side effects. People who use this medication should work closely with their healthcare practitioner to find the dosage that works the best for them.

In general, if levetiracetam test results are within the therapeutic range (or at an individually established level) and the treated person is not having recurrent seizures and is not experiencing significant side effects, then the drug dosage is considered adequate.

A level that is outside the therapeutic range may mean an individual is not taking the drug as prescribed. This is important to know since this may put the person at increased risk of experiencing symptoms.

People should not increase, decrease, or stop taking their medication without consulting with their healthcare practitioner. Dosage determinations and adjustments must be evaluated on a case-by-case basis.

People who have epilepsy will typically take levetiracetam or other medications throughout their lifetime. If levetiracetam ceases to be effective or causes adverse effects, then the person may need to be given different drug(s).

There are a broad range of AEDs available that have different forms of action and are used to treat different types of seizures. First-generation AEDs that have been use for a long period of time include: phenobarbital (since the early 1900s), phenytoin, carbamazepine, ethosuximide, and valproate (valproic acid). Newer, second-generation AEDs include drugs such as: gabapentin, lamotrigine, oxcarbazepine, topiramate, and levetiracetam. Some of these are used by themselves, but most of the newer AEDs are used in combination with other drugs.

Ask a Laboratory Scientist

Your questions will be answered by a laboratory scientist as part of a voluntary service provided by one of our partners, the American Society for Clinical Laboratory Science (ASCLS). Click on the Contact a Scientist button below to be re-directed to the ASCLS site to complete a request form. If your question relates to this web site and not to a specific lab test, please submit it via our Contact Us page instead. Thank you.